Research Information System
Journal of Molecular Structure, vol.1364, 2026 (SCI-Expanded, Scopus)
A tetrahydrocarbazole-based acylhydrazone receptor (PyThc) was designed and synthesized as an optical probe for fluoride (F⁻) in DMSO. PyThc shows a selective colorimetric/UV–vis response to F⁻ over common anions (Cl⁻, Br⁻, I⁻, CN⁻, ClO₄⁻, H₂PO₄⁻, HSO₄⁻, NO₃⁻, AcO⁻).1H NMR titrations indicate a stepwise process: the amide N–H signal disappears at low F⁻ equivalents, the indole N–H is suppressed at higher equivalents, and a broad resonance near 16 ppm emerges, consistent with [HF₂]⁻ formation. Dispersion-corrected DFT (ωB97X-D/def2-TZVP, PCM/DMSO) was used to rank ground-state conformers and rationalize duplicated NMR sets; the Z-amide/E-imine conformer is most stable, and an O=C–N–H torsional scan predicts an 18–20 kcal·mol⁻¹ barrier consistent with slow exchange. TD-DFT reproduces the neutral band (∼270 nm) and predicts a red-shifted transition (∼330 nm) for the deprotonated form, supporting selective fluoride sensing.